1. Field of the Invention
The present invention relates to, so-called, hybrid transmission and its assembling method suitable for a hybrid vehicle in which a plurality of power sources such as an engine (a prime mover) and a motor are mounted. The present invention particularly relates to the hybrid transmission and its assembling method which are capable of performing a continuously variable transmission operation through a differential unit such as a planetary gear mechanism.
2. Description of the Related Art
A Japanese Patent Application First Publication No. 2000-142146 published on May 23, 2000 exemplifies a previously proposed hybrid transmission using such a kind of differential unit as described above. In the previously proposed hybrid transmission, three rotary members of a sun gear, a carrier, and a ring gear constitute a planetary gear mechanism. A two-degree of freedom differential unit determines a rotating state of the other member if two of the three rotary members determine rotation states thereof is provided as the planetary gear mechanism and, in an order of revolution speeds, a generator, an input from an engine, an output to a drive system, and motor/generator are sequentially coupled to the three rotary members in an order of revolution speed so as to constitute the hybrid transmission. According to the previously proposed hybrid transmission, a differential function of the differential unit is utilized to provide a part of engine output for the drive of a generator and the supply of the generated power by the generator permits an increase or a decrease of a continuously variable transmission and an output torque.